Patent Reference 1 discloses a transmission system which relays and transmits Extended Display Identification Data (EDID) information wirelessly according to the HDMI.
FIG. 15 is a block diagram showing a structure of a conventional wireless communications system. The conventional wireless communications system includes a source device 1501, a sink device 1504, an adaptor device for the source device 1502, and an adapter device for the sink device 1503.
First, a control unit 1514 in the adapter device for the sink device 1503 reads an EDID table 1520 from a storage unit 1519, and stores the EDID table 1520 on an EDID table 1516 in a storage unit 1515 via a wired transmitting and receiving unit 1513, a cable C2, a wired transmitting and receiving unit 1517, and a control unit 1518.
The source device 1501 wirelessly transmits an authentication requesting signal to the sink device 1504 via a cable C1, a wired transmitting and receiving unit 1505, a wireless transmitting and receiving unit 1506, and an antenna 1510. Upon executing the authentication in response to the authentication requesting signal received via an antenna 1511, a wireless transmitting and receiving unit 1512, the wired transmitting and receiving unit 1513, and the cable C2, the sink device 1504 wirelessly transmits an authentication responding signal to the source device 1501 via the cable C2 and the adapter device for the sink device 1503. Upon receiving the authentication responding signal via the antenna 1510, the wireless transmitting and receiving unit 1506, the wired transmitting and receiving unit 1505, and the cable C1, the source device 1501 wirelessly transmits an EDID requesting signal to the sink device 1504 via the cable C1 and the adapter device for the source device 1502.
The control unit 1514 in the adapter device for the sink device 1503 generates an EDID responding signal in response to the EDID requesting signal via the antenna 1511 and the wireless transmitting and receiving unit 1512, and wirelessly transmits the generated EDID signal to the source device 1501. Here the EDID responding signal includes EDID information stored in the EDID table 1516 recorded on the storage unit 1515.
A control unit 1507 in the adapter device for the source device 1502 receives the EDID responding signal via the antenna 1510 and the wireless transmitting and receiving unit 1506, and stores the EDID information in an EDID table 1509 included in a storage unit 1508.
The source device 1501 wirelessly transmits a connection completion notifying signal to the sink device 1504 via the cable C1, the wired transmitting and receiving unit 1505, the wireless transmitting and receiving unit 1506, and the antenna 1510. Upon receiving the connection completion notifying signal via the adapter device for the sink device 1503 and the cable C2, the sink device 1504 wirelessly transmits the connection completion notifying signal to the source device 1501 via the cable C2 and the adapter device for the sink device 1503.
When the wireless connection is established as described above, the sink device 1504 wirelessly transmits a device designating signal via the cable C2 and the adapter device for the sink device 1503 in order to select the source device 1501 as a communications partner. Upon receiving the device designating signal via the adapter device for the source device 1502 and the cable C1, the source device 1501 wirelessly transmits an ACK signal to the sink device 1504 in response to the device designating signal. Then audio and visual (AV) data is started to be transmitted between the sink device 1504 and the source device 1501 via the adapter device for the source device 1502 and the adapter device for the sink device 1503.
As described above, the conventional wireless communications system disclosed in Patent Literature 1 allows the sink device 1504 and the source device 1501, both of which only include wired interfaces, to transmit and receive the EDID information via a wireless line since the adapter device for the sink device 1503 and the adapter device for the source device 1502 are respectively attached to the sink device 1504 and the source device 1501.